101
|
Foxp1 in Forebrain Pyramidal Neurons Controls Gene Expression Required for Spatial Learning and Synaptic Plasticity. J Neurosci 2017; 37:10917-10931. [PMID: 28978667 DOI: 10.1523/jneurosci.1005-17.2017] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 09/12/2017] [Accepted: 09/14/2017] [Indexed: 12/28/2022] Open
Abstract
Genetic perturbations of the transcription factor Forkhead Box P1 (FOXP1) are causative for severe forms of autism spectrum disorder that are often comorbid with intellectual disability. Recent work has begun to reveal an important role for FoxP1 in brain development, but the brain-region-specific contributions of Foxp1 to autism and intellectual disability phenotypes have yet to be determined fully. Here, we describe Foxp1 conditional knock-out (Foxp1cKO) male and female mice with loss of Foxp1 in the pyramidal neurons of the neocortex and the CA1/CA2 subfields of the hippocampus. Foxp1cKO mice exhibit behavioral phenotypes that are of potential relevance to autism spectrum disorder, including hyperactivity, increased anxiety, communication impairments, and decreased sociability. In addition, Foxp1cKO mice have gross deficits in learning and memory tasks of relevance to intellectual disability. Using a genome-wide approach, we identified differentially expressed genes in the hippocampus of Foxp1cKO mice associated with synaptic function and development. Furthermore, using magnetic resonance imaging, we uncovered a significant reduction in the volumes of both the entire hippocampus as well as individual hippocampal subfields of Foxp1cKO mice. Finally, we observed reduced maintenance of LTP in area CA1 of the hippocampus in these mutant mice. Together, these data suggest that proper expression of Foxp1 in the pyramidal neurons of the forebrain is important for regulating gene expression pathways that contribute to specific behaviors reminiscent of those seen in autism and intellectual disability. In particular, Foxp1 regulation of gene expression appears to be crucial for normal hippocampal development, CA1 plasticity, and spatial learning.SIGNIFICANCE STATEMENT Loss-of-function mutations in the transcription factor Forkhead Box P1 (FOXP1) lead to autism spectrum disorder and intellectual disability. Understanding the potential brain-region-specific contributions of FOXP1 to disease-relevant phenotypes could be a critical first step in the management of patients with these mutations. Here, we report that Foxp1 conditional knock-out (Foxp1cKO) mice with loss of Foxp1 in the neocortex and hippocampus display autism and intellectual-disability-relevant behaviors. We also show that these phenotypes correlate with changes in both the genomic and physiological profiles of the hippocampus in Foxp1cKO mice. Our work demonstrates that brain-region-specific FOXP1 expression may relate to distinct, clinically relevant phenotypes.
Collapse
|
102
|
Mitjans M, Begemann M, Ju A, Dere E, Wüstefeld L, Hofer S, Hassouna I, Balkenhol J, Oliveira B, van der Auwera S, Tammer R, Hammerschmidt K, Völzke H, Homuth G, Cecconi F, Chowdhury K, Grabe H, Frahm J, Boretius S, Dandekar T, Ehrenreich H. Sexual dimorphism of AMBRA1-related autistic features in human and mouse. Transl Psychiatry 2017; 7:e1247. [PMID: 28994820 PMCID: PMC5682605 DOI: 10.1038/tp.2017.213] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/01/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
Ambra1 is linked to autophagy and neurodevelopment. Heterozygous Ambra1 deficiency induces autism-like behavior in a sexually dimorphic manner. Extraordinarily, autistic features are seen in female mice only, combined with stronger Ambra1 protein reduction in brain compared to males. However, significance of AMBRA1 for autistic phenotypes in humans and, apart from behavior, for other autism-typical features, namely early brain enlargement or increased seizure propensity, has remained unexplored. Here we show in two independent human samples that a single normal AMBRA1 genotype, the intronic SNP rs3802890-AA, is associated with autistic features in women, who also display lower AMBRA1 mRNA expression in peripheral blood mononuclear cells relative to female GG carriers. Located within a non-coding RNA, likely relevant for mRNA and protein interaction, rs3802890 (A versus G allele) may affect its stability through modification of folding, as predicted by in silico analysis. Searching for further autism-relevant characteristics in Ambra1+/- mice, we observe reduced interest of female but not male mutants regarding pheromone signals of the respective other gender in the social intellicage set-up. Moreover, altered pentylentetrazol-induced seizure propensity, an in vivo readout of neuronal excitation-inhibition dysbalance, becomes obvious exclusively in female mutants. Magnetic resonance imaging reveals mild prepubertal brain enlargement in both genders, uncoupling enhanced brain dimensions from the primarily female expression of all other autistic phenotypes investigated here. These data support a role of AMBRA1/Ambra1 partial loss-of-function genotypes for female autistic traits. Moreover, they suggest Ambra1 heterozygous mice as a novel multifaceted and construct-valid genetic mouse model for female autism.
Collapse
Affiliation(s)
- M Mitjans
- Department of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - M Begemann
- Department of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany,Department of Psychiatry and Psychotherapy, UMG, Georg-August-University, Göttingen, Germany
| | - A Ju
- Department of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - E Dere
- Department of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - L Wüstefeld
- Department of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - S Hofer
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - I Hassouna
- Department of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - J Balkenhol
- Department of Bioinformatics, Biocenter, University of Würzburg, Würzburg, Germany
| | - B Oliveira
- Department of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - S van der Auwera
- Department of Psychiatry and Psychotherapy, University Medicine, and German Center for Neurodegenerative Diseases (DZNE) Greifswald, Greifswald, Germany
| | - R Tammer
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - K Hammerschmidt
- Cognitive Ethology Laboratory, German Primate Center, Göttingen, Germany
| | - H Völzke
- Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany
| | - G Homuth
- Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - F Cecconi
- IRCCS Fondazione Santa Lucia and Department of Biology, University of Rome Tor Vergata, Rome, Italy,Unit of Cell Stress and Survival, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - K Chowdhury
- Department of Molecular Cell Biology, Max Planck Institute of Biophysical Chemistry, Göttingen, Germany
| | - H Grabe
- Department of Psychiatry and Psychotherapy, University Medicine, and German Center for Neurodegenerative Diseases (DZNE) Greifswald, Greifswald, Germany
| | - J Frahm
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - S Boretius
- Department of Functional Imaging, German Primate Center, Leibniz Institute of Primate Research, Göttingen, Germany
| | - T Dandekar
- Department of Bioinformatics, Biocenter, University of Würzburg, Würzburg, Germany
| | - H Ehrenreich
- Department of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany,Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Hermann-Rein-Str. 3, Göttingen 37075, Germany. E-mail:
| |
Collapse
|
103
|
Misregulation of an Activity-Dependent Splicing Network as a Common Mechanism Underlying Autism Spectrum Disorders. Mol Cell 2017; 64:1023-1034. [PMID: 27984743 DOI: 10.1016/j.molcel.2016.11.033] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 10/27/2016] [Accepted: 11/22/2016] [Indexed: 12/22/2022]
Abstract
A key challenge in understanding and ultimately treating autism is to identify common molecular mechanisms underlying this genetically heterogeneous disorder. Transcriptomic profiling of autistic brains has revealed correlated misregulation of the neuronal splicing regulator nSR100/SRRM4 and its target microexon splicing program in more than one-third of analyzed individuals. To investigate whether nSR100 misregulation is causally linked to autism, we generated mutant mice with reduced levels of this protein and its target splicing program. Remarkably, these mice display multiple autistic-like features, including altered social behaviors, synaptic density, and signaling. Moreover, increased neuronal activity, which is often associated with autism, results in a rapid decrease in nSR100 and splicing of microexons that significantly overlap those misregulated in autistic brains. Collectively, our results provide evidence that misregulation of an nSR100-dependent splicing network controlled by changes in neuronal activity is causally linked to a substantial fraction of autism cases.
Collapse
|
104
|
Pinggera A, Mackenroth L, Rump A, Schallner J, Beleggia F, Wollnik B, Striessnig J. New gain-of-function mutation shows CACNA1D as recurrently mutated gene in autism spectrum disorders and epilepsy. Hum Mol Genet 2017; 26:2923-2932. [PMID: 28472301 PMCID: PMC5886262 DOI: 10.1093/hmg/ddx175] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 05/01/2017] [Accepted: 05/02/2017] [Indexed: 11/12/2022] Open
Abstract
CACNA1D encodes the pore-forming α1-subunit of Cav1.3, an L-type voltage-gated Ca2+-channel. Despite the recent discovery of two de novo missense gain-of-function mutations in Cav1.3 in two individuals with autism spectrum disorder (ASD) and intellectual disability CACNA1D has not been considered a prominent ASD-risk gene in large scale genetic analyses, since such studies primarily focus on likely-disruptive genetic variants. Here we report the discovery and characterization of a third de novo missense mutation in CACNA1D (V401L) in a patient with ASD and epilepsy. For the functional characterization we introduced mutation V401L into two major C-terminal long and short Cav1.3 splice variants, expressed wild-type or mutant channel complexes in tsA-201 cells and performed whole-cell patch-clamp recordings. Mutation V401L, localized within the channel's activation gate, significantly enhanced current densities, shifted voltage dependence of activation and inactivation to more negative voltages and reduced channel inactivation in both Cav1.3 splice variants. Altogether, these gating changes are expected to result in enhanced Ca2+-influx through the channel, thus representing a strong gain-of-function phenotype. Additionally, we also found that mutant channels retained full sensitivity towards the clinically available Ca2+ -channel blocker isradipine. Our findings strengthen the evidence for CACNA1D as a novel candidate autism risk gene and encourage experimental therapy with available channel-blockers for this mutation. The additional presence of seizures and neurological abnormalities in our patient define a novel phenotype partially overlapping with symptoms in two individuals with PASNA (congenital primary aldosteronism, seizures and neurological abnormalities) caused by similar Cav1.3 gain-of-function mutations.
Collapse
Affiliation(s)
- Alexandra Pinggera
- Department of Pharmacology and Toxicology Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| | | | | | - Jens Schallner
- Abteilung Neuropädiatrie, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Filippo Beleggia
- Department I of Internal Medicine, University Hospital of Cologne, 50923 Cologne, Germany
| | - Bernd Wollnik
- Institute of Human Genetics, University Medical Center Göttingen, 37073 Göttingen, Germany
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria
| |
Collapse
|
105
|
Rescue of impaired sociability and anxiety-like behavior in adult cacna1c-deficient mice by pharmacologically targeting eIF2α. Mol Psychiatry 2017; 22:1096-1109. [PMID: 28584287 PMCID: PMC5863913 DOI: 10.1038/mp.2017.124] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 04/12/2017] [Accepted: 05/04/2017] [Indexed: 12/13/2022]
Abstract
CACNA1C, encoding the Cav1.2 subunit of L-type Ca2+ channels, has emerged as one of the most prominent and highly replicable susceptibility genes for several neuropsychiatric disorders. Cav1.2 channels play a crucial role in calcium-mediated processes involved in brain development and neuronal function. Within the CACNA1C gene, disease-associated single-nucleotide polymorphisms have been associated with impaired social and cognitive processing and altered prefrontal cortical (PFC) structure and activity. These findings suggest that aberrant Cav1.2 signaling may contribute to neuropsychiatric-related disease symptoms via impaired PFC function. Here, we show that mice harboring loss of cacna1c in excitatory glutamatergic neurons of the forebrain (fbKO) that we have previously reported to exhibit anxiety-like behavior, displayed a social behavioral deficit and impaired learning and memory. Furthermore, focal knockdown of cacna1c in the adult PFC recapitulated the social deficit and elevated anxiety-like behavior, but not the deficits in learning and memory. Electrophysiological and molecular studies in the PFC of cacna1c fbKO mice revealed higher E/I ratio in layer 5 pyramidal neurons and lower general protein synthesis. This was concurrent with reduced activity of mTORC1 and its downstream mRNA translation initiation factors eIF4B and 4EBP1, as well as elevated phosphorylation of eIF2α, an inhibitor of mRNA translation. Remarkably, systemic treatment with ISRIB, a small molecule inhibitor that suppresses the effects of phosphorylated eIF2α on mRNA translation, was sufficient to reverse the social deficit and elevated anxiety-like behavior in adult cacna1c fbKO mice. ISRIB additionally normalized the lower protein synthesis and higher E/I ratio in the PFC. Thus this study identifies a novel Cav1.2 mechanism in neuropsychiatric-related endophenotypes and a potential future therapeutic target to explore.
Collapse
|
106
|
Kabir ZD, Martínez-Rivera A, Rajadhyaksha AM. From Gene to Behavior: L-Type Calcium Channel Mechanisms Underlying Neuropsychiatric Symptoms. Neurotherapeutics 2017; 14:588-613. [PMID: 28497380 PMCID: PMC5509628 DOI: 10.1007/s13311-017-0532-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The L-type calcium channels (LTCCs) Cav1.2 and Cav1.3, encoded by the CACNA1C and CACNA1D genes, respectively, are important regulators of calcium influx into cells and are critical for normal brain development and plasticity. In humans, CACNA1C has emerged as one of the most widely reproduced and prominent candidate risk genes for a range of neuropsychiatric disorders, including bipolar disorder (BD), schizophrenia (SCZ), major depressive disorder, autism spectrum disorder, and attention deficit hyperactivity disorder. Separately, CACNA1D has been found to be associated with BD and autism spectrum disorder, as well as cocaine dependence, a comorbid feature associated with psychiatric disorders. Despite growing evidence of a significant link between CACNA1C and CACNA1D and psychiatric disorders, our understanding of the biological mechanisms by which these LTCCs mediate neuropsychiatric-associated endophenotypes, many of which are shared across the different disorders, remains rudimentary. Clinical studies with LTCC blockers testing their efficacy to alleviate symptoms associated with BD, SCZ, and drug dependence have provided mixed results, underscoring the importance of further exploring the neurobiological consequences of dysregulated Cav1.2 and Cav1.3. Here, we provide a review of clinical studies that have evaluated LTCC blockers for BD, SCZ, and drug dependence-associated symptoms, as well as rodent studies that have identified Cav1.2- and Cav1.3-specific molecular and cellular cascades that underlie mood (anxiety, depression), social behavior, cognition, and addiction.
Collapse
Affiliation(s)
- Zeeba D Kabir
- Pediatric Neurology, Pediatrics, Weill Cornell Medicine, New York, NY, USA
- Weill Cornell Autism Research Program, Weill Cornell Medicine, New York, NY, USA
| | - Arlene Martínez-Rivera
- Pediatric Neurology, Pediatrics, Weill Cornell Medicine, New York, NY, USA
- Weill Cornell Autism Research Program, Weill Cornell Medicine, New York, NY, USA
| | - Anjali M Rajadhyaksha
- Pediatric Neurology, Pediatrics, Weill Cornell Medicine, New York, NY, USA.
- Weill Cornell Autism Research Program, Weill Cornell Medicine, New York, NY, USA.
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
| |
Collapse
|
107
|
Mosca TJ, Luginbuhl DJ, Wang IE, Luo L. Presynaptic LRP4 promotes synapse number and function of excitatory CNS neurons. eLife 2017; 6. [PMID: 28606304 PMCID: PMC5469616 DOI: 10.7554/elife.27347] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/08/2017] [Indexed: 12/24/2022] Open
Abstract
Precise coordination of synaptic connections ensures proper information flow within circuits. The activity of presynaptic organizing molecules signaling to downstream pathways is essential for such coordination, though such entities remain incompletely known. We show that LRP4, a conserved transmembrane protein known for its postsynaptic roles, functions presynaptically as an organizing molecule. In the Drosophila brain, LRP4 localizes to the nerve terminals at or near active zones. Loss of presynaptic LRP4 reduces excitatory (not inhibitory) synapse number, impairs active zone architecture, and abolishes olfactory attraction - the latter of which can be suppressed by reducing presynaptic GABAB receptors. LRP4 overexpression increases synapse number in excitatory and inhibitory neurons, suggesting an instructive role and a common downstream synapse addition pathway. Mechanistically, LRP4 functions via the conserved kinase SRPK79D to ensure normal synapse number and behavior. This highlights a presynaptic function for LRP4, enabling deeper understanding of how synapse organization is coordinated.
Collapse
Affiliation(s)
- Timothy J Mosca
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, United States.,Department of Biology, Howard Hughes Medical Institute, Stanford University, Stanford, United States
| | - David J Luginbuhl
- Department of Biology, Howard Hughes Medical Institute, Stanford University, Stanford, United States
| | - Irving E Wang
- Department of Neurobiology, Stanford University, Stanford, United States
| | - Liqun Luo
- Department of Biology, Howard Hughes Medical Institute, Stanford University, Stanford, United States
| |
Collapse
|
108
|
Genç Ö, Dickman DK, Ma W, Tong A, Fetter RD, Davis GW. MCTP is an ER-resident calcium sensor that stabilizes synaptic transmission and homeostatic plasticity. eLife 2017; 6. [PMID: 28485711 PMCID: PMC5449185 DOI: 10.7554/elife.22904] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 05/08/2017] [Indexed: 12/26/2022] Open
Abstract
Presynaptic homeostatic plasticity (PHP) controls synaptic transmission in organisms from Drosophila to human and is hypothesized to be relevant to the cause of human disease. However, the underlying molecular mechanisms of PHP are just emerging and direct disease associations remain obscure. In a forward genetic screen for mutations that block PHP we identified mctp (Multiple C2 Domain Proteins with Two Transmembrane Regions). Here we show that MCTP localizes to the membranes of the endoplasmic reticulum (ER) that elaborate throughout the soma, dendrites, axon and presynaptic terminal. Then, we demonstrate that MCTP functions downstream of presynaptic calcium influx with separable activities to stabilize baseline transmission, short-term release dynamics and PHP. Notably, PHP specifically requires the calcium coordinating residues in each of the three C2 domains of MCTP. Thus, we propose MCTP as a novel, ER-localized calcium sensor and a source of calcium-dependent feedback for the homeostatic stabilization of neurotransmission.
Collapse
Affiliation(s)
- Özgür Genç
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Dion K Dickman
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States.,Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Wenpei Ma
- Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Amy Tong
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Richard D Fetter
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| |
Collapse
|
109
|
Yu X, Qiu Z, Zhang D. Recent Research Progress in Autism Spectrum Disorder. Neurosci Bull 2017; 33:125-129. [PMID: 28285467 PMCID: PMC5567533 DOI: 10.1007/s12264-017-0117-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 11/24/2022] Open
Affiliation(s)
- Xiang Yu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Zilong Qiu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Dai Zhang
- Institute of Mental Health, Peking University Sixth Hospital, Beijing, 100191, China.
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
- PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China.
| |
Collapse
|
110
|
Zhang X, Sullivan CS, Kratz MB, Kasten MR, Maness PF, Manis PB. NCAM Regulates Inhibition and Excitability in Layer 2/3 Pyramidal Cells of Anterior Cingulate Cortex. Front Neural Circuits 2017; 11:19. [PMID: 28386219 PMCID: PMC5362729 DOI: 10.3389/fncir.2017.00019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 03/06/2017] [Indexed: 11/29/2022] Open
Abstract
The neural cell adhesion molecule (NCAM), has been shown to be an obligate regulator of synaptic stability and pruning during critical periods of cortical maturation. However, the functional consequences of NCAM deletion on the organization of inhibitory circuits in cortex are not known. In vesicular gamma-amino butyric acid (GABA) transporter (VGAT)-channelrhodopsin2 (ChR2)-enhanced yellow fluorescent protein (EYFP) transgenic mice, NCAM is expressed postnatally at perisomatic synaptic puncta of EYFP-labeled parvalbumin, somatostatin and calretinin-positive interneurons, and in the neuropil in the anterior cingulate cortex (ACC). To investigate how NCAM deletion affects the spatial organization of inhibitory inputs to pyramidal cells, we used laser scanning photostimulation in brain slices of VGAT-ChR2-EYFP transgenic mice crossed to either NCAM-null or wild type (WT) mice. Laser scanning photostimulation revealed that NCAM deletion increased the strength of close-in inhibitory connections to layer 2/3 pyramidal cells of the ACC. In addition, in NCAM-null mice, the intrinsic excitability of pyramidal cells increased, whereas the intrinsic excitability of GABAergic interneurons did not change. The increase in inhibitory tone onto pyramidal cells, and the increased pyramidal cell excitability in NCAM-null mice will alter the delicate coordination of excitation and inhibition (E/I coordination) in the ACC, and may be a factor contributing to circuit dysfunction in diseases such as schizophrenia and bipolar disorder, in which NCAM has been implicated.
Collapse
Affiliation(s)
- Xuying Zhang
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Chelsea S Sullivan
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Megan B Kratz
- Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Michael R Kasten
- Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Patricia F Maness
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill Chapel Hill, NC, USA
| | - Paul B Manis
- Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel HillChapel Hill, NC, USA; Department of Cell Biology and Physiology, The University of North Carolina at Chapel HillChapel Hill, NC, USA
| |
Collapse
|
111
|
Wang M, Li H, Takumi T, Qiu Z, Xu X, Yu X, Bian WJ. Distinct Defects in Spine Formation or Pruning in Two Gene Duplication Mouse Models of Autism. Neurosci Bull 2017; 33:143-152. [PMID: 28258509 PMCID: PMC5360848 DOI: 10.1007/s12264-017-0111-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 02/13/2017] [Indexed: 11/11/2022] Open
Abstract
Autism spectrum disorder (ASD) encompasses a complex set of developmental neurological disorders, characterized by deficits in social communication and excessive repetitive behaviors. In recent years, ASD is increasingly being considered as a disease of the synapse. One main type of genetic aberration leading to ASD is gene duplication, and several mouse models have been generated mimicking these mutations. Here, we studied the effects of MECP2 duplication and human chromosome 15q11-13 duplication on synaptic development and neural circuit wiring in the mouse sensory cortices. We showed that mice carrying MECP2 duplication had specific defects in spine pruning, while the 15q11-13 duplication mouse model had impaired spine formation. Our results demonstrate that spine pathology varies significantly between autism models and that distinct aspects of neural circuit development may be targeted in different ASD mutations. Our results further underscore the importance of gene dosage in normal development and function of the brain.
Collapse
Affiliation(s)
- Miao Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Huiping Li
- Department of Child Healthcare, Children's Hospital of Fudan University, Shanghai, 201102, China
| | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
| | - Zilong Qiu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Xiu Xu
- Department of Child Healthcare, Children's Hospital of Fudan University, Shanghai, 201102, China.
| | - Xiang Yu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Wen-Jie Bian
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
| |
Collapse
|
112
|
McCarthy MM, Wright CL. Convergence of Sex Differences and the Neuroimmune System in Autism Spectrum Disorder. Biol Psychiatry 2017; 81:402-410. [PMID: 27871670 PMCID: PMC5285451 DOI: 10.1016/j.biopsych.2016.10.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 09/14/2016] [Accepted: 10/04/2016] [Indexed: 01/06/2023]
Abstract
The male bias in autism spectrum disorder incidence is among the most extreme of all neuropsychiatric disorders, yet the origins of the sex difference remain obscure. Developmentally, males are exposed to high levels of testosterone and its byproduct, estradiol. Together these steroids modify the course of brain development by altering neurogenesis, cell death, migration, differentiation, dendritic and axonal growth, synaptogenesis, and synaptic pruning, all of which can be deleteriously impacted during the course of developmental neuropsychiatric disorders. Elucidating the cellular mechanisms by which steroids modulate brain development provides valuable insights into how these processes may go awry. An emerging theme is the role of inflammatory signaling molecules and the innate immune system in directing brain masculinization, the evidence for which we review here. Evidence is also emerging that the neuroimmune system is overactivated in individuals with autism spectrum disorder. These combined observations lead us to propose that the natural process of brain masculinization puts males at risk by moving them closer to a vulnerability threshold that could more easily be breached by inflammation during critical periods of brain development. Two brain regions are highlighted: the preoptic area and the cerebellum. Both are developmentally regulated by the inflammatory prostaglandin E2, but in different ways. Microglia, innate immune cells of the brain, and astrocytes are also critical contributors to masculinization and illustrate the importance of nonneuronal cells to the health of the developing brain.
Collapse
Affiliation(s)
- Margaret M McCarthy
- Department of Pharmacology and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland.
| | - Christopher L Wright
- Department of Pharmacology and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland
| |
Collapse
|
113
|
Abstract
Purpose of Review Pitt Hopkins syndrome (PTHS) is a rare neurodevelopmental disorder that results from mutations of the clinically pleiotropic Transcription Factor 4 (TCF4) gene. Mutations in the genomic locus of TCF4 on chromosome 18 have been linked to multiple disorders including 18q syndrome, schizophrenia, Fuch's corneal dystrophy, and sclerosing cholangitis. For PTHS, TCF4 mutation or deletion leads to the production of a dominant negative TCF4 protein and/or haploinsufficiency that results in abnormal brain development. The biology of TCF4 has been studied for several years in regards to its role in immune cell differentiation, although its role in neurodevelopment and the mechanisms resulting in the severe symptoms of PTHS are not well studied. Recent Findings Here, we summarize the current understanding of PTHS and recent findings that have begun to describe the biological implications of TCF4 deficiency during brain development and into adulthood. In particular, we focus on recent work that has looked at the role of TCF4 biology within the context of PTHS and highlight the potential for identification of therapeutic targets for PTHS. Summary PTHS research continues to uncover mutations in TCF4 that underlie the genetic cause of this rare disease, and emerging evidence for molecular mechanisms that TCF4 regulates in brain development and neuronal function is contributing to a more complete picture of how pathology arises from this genetic basis, with important implications for the potential of future clinical care.
Collapse
|
114
|
Mastwal S, Cao V, Wang KH. Genetic Feedback Regulation of Frontal Cortical Neuronal Ensembles Through Activity-Dependent Arc Expression and Dopaminergic Input. Front Neural Circuits 2016; 10:100. [PMID: 27999532 PMCID: PMC5138219 DOI: 10.3389/fncir.2016.00100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/23/2016] [Indexed: 12/15/2022] Open
Abstract
Mental functions involve coordinated activities of specific neuronal ensembles that are embedded in complex brain circuits. Aberrant neuronal ensemble dynamics is thought to form the neurobiological basis of mental disorders. A major challenge in mental health research is to identify these cellular ensembles and determine what molecular mechanisms constrain their emergence and consolidation during development and learning. Here, we provide a perspective based on recent studies that use activity-dependent gene Arc/Arg3.1 as a cellular marker to identify neuronal ensembles and a molecular probe to modulate circuit functions. These studies have demonstrated that the transcription of Arc is activated in selective groups of frontal cortical neurons in response to specific behavioral tasks. Arc expression regulates the persistent firing of individual neurons and predicts the consolidation of neuronal ensembles during repeated learning. Therefore, the Arc pathway represents a prototypical example of activity-dependent genetic feedback regulation of neuronal ensembles. The activation of this pathway in the frontal cortex starts during early postnatal development and requires dopaminergic (DA) input. Conversely, genetic disruption of Arc leads to a hypoactive mesofrontal dopamine circuit and its related cognitive deficit. This mutual interaction suggests an auto-regulatory mechanism to amplify the impact of neuromodulators and activity-regulated genes during postnatal development. Such a mechanism may contribute to the association of mutations in dopamine and Arc pathways with neurodevelopmental psychiatric disorders. As the mesofrontal dopamine circuit shows extensive activity-dependent developmental plasticity, activity-guided modulation of DA projections or Arc ensembles during development may help to repair circuit deficits related to neuropsychiatric disorders.
Collapse
Affiliation(s)
- Surjeet Mastwal
- Unit on Neural Circuits and Adaptive Behaviors, Clinical and Translational Neuroscience Branch, National Institute of Mental Health Bethesda, MD, USA
| | - Vania Cao
- Unit on Neural Circuits and Adaptive Behaviors, Clinical and Translational Neuroscience Branch, National Institute of Mental Health Bethesda, MD, USA
| | - Kuan Hong Wang
- Unit on Neural Circuits and Adaptive Behaviors, Clinical and Translational Neuroscience Branch, National Institute of Mental Health Bethesda, MD, USA
| |
Collapse
|
115
|
Genome-wide changes in lncRNA, splicing, and regional gene expression patterns in autism. Nature 2016; 540:423-427. [PMID: 27919067 DOI: 10.1038/nature20612] [Citation(s) in RCA: 443] [Impact Index Per Article: 55.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 11/07/2016] [Indexed: 12/11/2022]
Abstract
Autism spectrum disorder (ASD) involves substantial genetic contributions. These contributions are profoundly heterogeneous but may converge on common pathways that are not yet well understood. Here, through post-mortem genome-wide transcriptome analysis of the largest cohort of samples analysed so far, to our knowledge, we interrogate the noncoding transcriptome, alternative splicing, and upstream molecular regulators to broaden our understanding of molecular convergence in ASD. Our analysis reveals ASD-associated dysregulation of primate-specific long noncoding RNAs (lncRNAs), downregulation of the alternative splicing of activity-dependent neuron-specific exons, and attenuation of normal differences in gene expression between the frontal and temporal lobes. Our data suggest that SOX5, a transcription factor involved in neuron fate specification, contributes to this reduction in regional differences. We further demonstrate that a genetically defined subtype of ASD, chromosome 15q11.2-13.1 duplication syndrome (dup15q), shares the core transcriptomic signature observed in idiopathic ASD. Co-expression network analysis reveals that individuals with ASD show age-related changes in the trajectory of microglial and synaptic function over the first two decades, and suggests that genetic risk for ASD may influence changes in regional cortical gene expression. Our findings illustrate how diverse genetic perturbations can lead to phenotypic convergence at multiple biological levels in a complex neuropsychiatric disorder.
Collapse
|
116
|
Kwan V, Unda BK, Singh KK. Wnt signaling networks in autism spectrum disorder and intellectual disability. J Neurodev Disord 2016; 8:45. [PMID: 27980692 PMCID: PMC5137220 DOI: 10.1186/s11689-016-9176-3] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 11/07/2016] [Indexed: 12/20/2022] Open
Abstract
Background Genetic factors play a major role in the risk for neurodevelopmental disorders such as autism spectrum disorders (ASDs) and intellectual disability (ID). The underlying genetic factors have become better understood in recent years due to advancements in next generation sequencing. These studies have uncovered a vast number of genes that are impacted by different types of mutations (e.g., de novo, missense, truncation, copy number variations). Abstract Given the large volume of genetic data, analyzing each gene on its own is not a feasible approach and will take years to complete, let alone attempt to use the information to develop novel therapeutics. To make sense of independent genomic data, one approach is to determine whether multiple risk genes function in common signaling pathways that identify signaling “hubs” where risk genes converge. This approach has led to multiple pathways being implicated, such as synaptic signaling, chromatin remodeling, alternative splicing, and protein translation, among many others. In this review, we analyze recent and historical evidence indicating that multiple risk genes, including genes denoted as high-confidence and likely causal, are part of the Wingless (Wnt signaling) pathway. In the brain, Wnt signaling is an evolutionarily conserved pathway that plays an instrumental role in developing neural circuits and adult brain function. Conclusions We will also review evidence that pharmacological therapies and genetic mouse models further identify abnormal Wnt signaling, particularly at the synapse, as being disrupted in ASDs and contributing to disease pathology.
Collapse
Affiliation(s)
- Vickie Kwan
- Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, Ontario L8S 4K1 Canada
| | - Brianna K Unda
- Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, Ontario L8S 4K1 Canada
| | - Karun K Singh
- Department of Biochemistry and Biomedical Sciences, Stem Cell and Cancer Research Institute, McMaster University, Hamilton, Ontario L8S 4K1 Canada
| |
Collapse
|
117
|
Lin YC, Frei JA, Kilander MBC, Shen W, Blatt GJ. A Subset of Autism-Associated Genes Regulate the Structural Stability of Neurons. Front Cell Neurosci 2016; 10:263. [PMID: 27909399 PMCID: PMC5112273 DOI: 10.3389/fncel.2016.00263] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/28/2016] [Indexed: 12/15/2022] Open
Abstract
Autism spectrum disorder (ASD) comprises a range of neurological conditions that affect individuals’ ability to communicate and interact with others. People with ASD often exhibit marked qualitative difficulties in social interaction, communication, and behavior. Alterations in neurite arborization and dendritic spine morphology, including size, shape, and number, are hallmarks of almost all neurological conditions, including ASD. As experimental evidence emerges in recent years, it becomes clear that although there is broad heterogeneity of identified autism risk genes, many of them converge into similar cellular pathways, including those regulating neurite outgrowth, synapse formation and spine stability, and synaptic plasticity. These mechanisms together regulate the structural stability of neurons and are vulnerable targets in ASD. In this review, we discuss the current understanding of those autism risk genes that affect the structural connectivity of neurons. We sub-categorize them into (1) cytoskeletal regulators, e.g., motors and small RhoGTPase regulators; (2) adhesion molecules, e.g., cadherins, NCAM, and neurexin superfamily; (3) cell surface receptors, e.g., glutamatergic receptors and receptor tyrosine kinases; (4) signaling molecules, e.g., protein kinases and phosphatases; and (5) synaptic proteins, e.g., vesicle and scaffolding proteins. Although the roles of some of these genes in maintaining neuronal structural stability are well studied, how mutations contribute to the autism phenotype is still largely unknown. Investigating whether and how the neuronal structure and function are affected when these genes are mutated will provide insights toward developing effective interventions aimed at improving the lives of people with autism and their families.
Collapse
Affiliation(s)
- Yu-Chih Lin
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Jeannine A Frei
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Michaela B C Kilander
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Wenjuan Shen
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Gene J Blatt
- Laboratory of Autism Neurocircuitry, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| |
Collapse
|
118
|
Neuronal Signaling: an introduction. Neuronal Signal 2016; 1:NS20160025. [PMID: 32714575 PMCID: PMC7377261 DOI: 10.1042/ns20160025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
There have been a number of advances in our knowledge of neuronal communication in processes involved in development, functioning and disorders of the nervous system. This progress has prompted the Biochemical Society to launch Neuronal Signaling, a new open access journal that aims to expand on the existing knowledge about signaling within and between neurons.
Collapse
|
119
|
Regulation of motoneuron excitability and the setting of homeostatic limits. Curr Opin Neurobiol 2016; 43:1-6. [PMID: 27721083 DOI: 10.1016/j.conb.2016.09.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/25/2016] [Accepted: 09/24/2016] [Indexed: 01/29/2023]
Abstract
Stability of neural circuits is reliant on homeostatic mechanisms that return neuron activity towards pre-determined and physiologically appropriate levels. Without these mechanisms, changes due to synaptic plasticity, ageing and disease may push neural circuits towards instability. Whilst widely documented, understanding of how and when neurons determine an appropriate activity level, the so-called set-point, remains unknown. Genetically tractable model systems have greatly contributed to our understanding of neuronal homeostasis and continue to offer attractive models to explore these additional questions. This review focuses on the development of Drosophila motoneurons including defining an embryonic critical period during which these neurons encode their set-points to enable homeostatic regulation of activity.
Collapse
|
120
|
Actin-Dependent Alterations of Dendritic Spine Morphology in Shankopathies. Neural Plast 2016; 2016:8051861. [PMID: 27795858 PMCID: PMC5067329 DOI: 10.1155/2016/8051861] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 08/30/2016] [Indexed: 12/11/2022] Open
Abstract
Shank proteins (Shank1, Shank2, and Shank3) act as scaffolding molecules in the postsynaptic density of many excitatory neurons. Mutations in SHANK genes, in particular SHANK2 and SHANK3, lead to autism spectrum disorders (ASD) in both human and mouse models. Shank3 proteins are made of several domains-the Shank/ProSAP N-terminal (SPN) domain, ankyrin repeats, SH3 domain, PDZ domain, a proline-rich region, and the sterile alpha motif (SAM) domain. Via various binding partners of these domains, Shank3 is able to bind and interact with a wide range of proteins including modulators of small GTPases such as RICH2, a RhoGAP protein, and βPIX, a RhoGEF protein for Rac1 and Cdc42, actin binding proteins and actin modulators. Dysregulation of all isoforms of Shank proteins, but especially Shank3, leads to alterations in spine morphogenesis, shape, and activity of the synapse via altering actin dynamics. Therefore, here, we highlight the role of Shank proteins as modulators of small GTPases and, ultimately, actin dynamics, as found in multiple in vitro and in vivo models. The failure to mediate this regulatory role might present a shared mechanism in the pathophysiology of autism-associated mutations, which leads to dysregulation of spine morphogenesis and synaptic signaling.
Collapse
|
121
|
Selten MM, Meyer F, Ba W, Vallès A, Maas DA, Negwer M, Eijsink VD, van Vugt RWM, van Hulten JA, van Bakel NHM, Roosen J, van der Linden RJ, Schubert D, Verheij MMM, Kasri NN, Martens GJM. Increased GABA B receptor signaling in a rat model for schizophrenia. Sci Rep 2016; 6:34240. [PMID: 27687783 PMCID: PMC5043235 DOI: 10.1038/srep34240] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 09/05/2016] [Indexed: 02/04/2023] Open
Abstract
Schizophrenia is a complex disorder that affects cognitive function and has been linked, both in patients and animal models, to dysfunction of the GABAergic system. However, the pathophysiological consequences of this dysfunction are not well understood. Here, we examined the GABAergic system in an animal model displaying schizophrenia-relevant features, the apomorphine-susceptible (APO-SUS) rat and its phenotypic counterpart, the apomorphine-unsusceptible (APO-UNSUS) rat at postnatal day 20-22. We found changes in the expression of the GABA-synthesizing enzyme GAD67 specifically in the prelimbic- but not the infralimbic region of the medial prefrontal cortex (mPFC), indicative of reduced inhibitory function in this region in APO-SUS rats. While we did not observe changes in basal synaptic transmission onto LII/III pyramidal cells in the mPFC of APO-SUS compared to APO-UNSUS rats, we report reduced paired-pulse ratios at longer inter-stimulus intervals. The GABAB receptor antagonist CGP 55845 abolished this reduction, indicating that the decreased paired-pulse ratio was caused by increased GABAB signaling. Consistently, we find an increased expression of the GABAB1 receptor subunit in APO-SUS rats. Our data provide physiological evidence for increased presynaptic GABAB signaling in the mPFC of APO-SUS rats, further supporting an important role for the GABAergic system in the pathophysiology of schizophrenia.
Collapse
Affiliation(s)
- Martijn M. Selten
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, the Netherlands
| | - Francisca Meyer
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
| | - Wei Ba
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, the Netherlands
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands
| | - Astrid Vallès
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Faculty of Psychology and Neurosciences, Maastricht University, Maastricht, the Netherlands
| | - Dorien A. Maas
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, the Netherlands
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
| | - Moritz Negwer
- Department of Language and Genetics, Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands
| | - Vivian D. Eijsink
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
| | - Ruben W. M. van Vugt
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
| | - Josephus A. van Hulten
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
| | - Nick H. M. van Bakel
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
| | - Joey Roosen
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
| | - Robert J. van der Linden
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
| | - Dirk Schubert
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, the Netherlands
| | - Michel M. M. Verheij
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, the Netherlands
| | - Nael Nadif Kasri
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, the Netherlands
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands
| | - Gerard J. M. Martens
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands
| |
Collapse
|
122
|
Huang WH, Guenthner CJ, Xu J, Nguyen T, Schwarz LA, Wilkinson AW, Gozani O, Chang HY, Shamloo M, Luo L. Molecular and Neural Functions of Rai1, the Causal Gene for Smith-Magenis Syndrome. Neuron 2016; 92:392-406. [PMID: 27693255 DOI: 10.1016/j.neuron.2016.09.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/13/2016] [Accepted: 09/09/2016] [Indexed: 12/24/2022]
Abstract
Haploinsufficiency of Retinoic Acid Induced 1 (RAI1) causes Smith-Magenis syndrome (SMS), which is associated with diverse neurodevelopmental and behavioral symptoms as well as obesity. RAI1 encodes a nuclear protein but little is known about its molecular function or the cell types responsible for SMS symptoms. Using genetically engineered mice, we found that Rai1 preferentially occupies DNA regions near active promoters and promotes the expression of a group of genes involved in circuit assembly and neuronal communication. Behavioral analyses demonstrated that pan-neural loss of Rai1 causes deficits in motor function, learning, and food intake. These SMS-like phenotypes are produced by loss of Rai1 function in distinct neuronal types: Rai1 loss in inhibitory neurons or subcortical glutamatergic neurons causes learning deficits, while Rai1 loss in Sim1+ or SF1+ cells causes obesity. By integrating molecular and organismal analyses, our study suggests potential therapeutic avenues for a complex neurodevelopmental disorder.
Collapse
Affiliation(s)
- Wei-Hsiang Huang
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Casey J Guenthner
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA; Neurosciences Program, Stanford University, Stanford, CA 94305, USA
| | - Jin Xu
- Center for Personal Dynamic Regulomes and Program in Epithelial Biology, Stanford University, Stanford, CA 94305, USA
| | - Tiffany Nguyen
- Stanford Behavioral and Functional Neuroscience Laboratory, Stanford University, Stanford, CA 94305, USA
| | - Lindsay A Schwarz
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Alex W Wilkinson
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Or Gozani
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes and Program in Epithelial Biology, Stanford University, Stanford, CA 94305, USA
| | - Mehrdad Shamloo
- Stanford Behavioral and Functional Neuroscience Laboratory, Stanford University, Stanford, CA 94305, USA; Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Liqun Luo
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA; Neurosciences Program, Stanford University, Stanford, CA 94305, USA.
| |
Collapse
|
123
|
Hepatocyte Growth Factor Modulates MET Receptor Tyrosine Kinase and β-Catenin Functional Interactions to Enhance Synapse Formation. eNeuro 2016; 3:eN-NWR-0074-16. [PMID: 27595133 PMCID: PMC5002983 DOI: 10.1523/eneuro.0074-16.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 07/19/2016] [Accepted: 07/25/2016] [Indexed: 01/09/2023] Open
Abstract
MET, a pleiotropic receptor tyrosine kinase implicated in autism risk, influences multiple neurodevelopmental processes. There is a knowledge gap, however, in the molecular mechanism through which MET mediates developmental events related to disorder risk. In the neocortex, MET is expressed transiently during periods of peak dendritic outgrowth and synaptogenesis, with expression enriched at developing synapses, consistent with demonstrated roles in dendritic morphogenesis, modulation of spine volume, and excitatory synapse development. In a recent coimmunoprecipitation/mass spectrometry screen, β-catenin was identified as part of the MET interactome in developing neocortical synaptosomes. Here, we investigated the influence of the MET/β-catenin complex in mouse neocortical synaptogenesis. Western blot analysis confirms that MET and β-catenin coimmunoprecipitate, but N-cadherin is not associated with the MET complex. Following stimulation with hepatocyte growth factor (HGF), β-catenin is phosphorylated at tyrosine142 (Y142) and dissociates from MET, accompanied by an increase in β-catenin/N-cadherin and MET/synapsin 1 protein complexes. In neocortical neurons in vitro, proximity ligation assays confirmed the close proximity of these proteins. Moreover, in neurons transfected with synaptophysin-GFP, HGF stimulation increases the density of synaptophysin/bassoon (a presynaptic marker) and synaptophysin/PSD-95 (a postsynaptic marker) clusters. Mutation of β-catenin at Y142 disrupts the dissociation of the MET/β-catenin complex and prevents the increase in clusters in response to HGF. The data demonstrate a new mechanism for the modulation of synapse formation, whereby MET activation induces an alignment of presynaptic and postsynaptic elements that are necessary for assembly and formation of functional synapses by subsets of neocortical neurons that express MET/β-catenin complex.
Collapse
|
124
|
Krencik R, van Asperen JV, Ullian EM. Human astrocytes are distinct contributors to the complexity of synaptic function. Brain Res Bull 2016; 129:66-73. [PMID: 27570101 DOI: 10.1016/j.brainresbull.2016.08.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 08/07/2016] [Accepted: 08/22/2016] [Indexed: 01/03/2023]
Abstract
Cellular components of synaptic circuits have been adjusted for increased human brain size, neural cell density, energy consumption and developmental duration. How does the human brain make these accommodations? There is evidence that astrocytes are one of the most divergent neural cell types in primate brain evolution and it is now becoming clear that they have critical roles in controlling synaptic development, function and plasticity. Yet, we still do not know how the precise developmental appearance of these cells and subsequent astrocyte-derived signals modulate diverse neuronal circuit subtypes. Here, we discuss what is currently known about the influence of glial factors on synaptic maturation and focus on unique features of human astrocytes including their potential roles in regenerative and translational medicine. Human astrocyte distinctiveness may be a major contributor to high level neuronal processing of the human brain and act in novel ways during various neuropathies ranging from autism spectrum disorders, viral infection, injury and neurodegenerative conditions.
Collapse
Affiliation(s)
- Robert Krencik
- Departments of Ophthalmology and Physiology, Neuroscience Program, University of California San Francisco, United States.
| | - Jessy V van Asperen
- Departments of Ophthalmology and Physiology, Neuroscience Program, University of California San Francisco, United States
| | - Erik M Ullian
- Departments of Ophthalmology and Physiology, Neuroscience Program, University of California San Francisco, United States
| |
Collapse
|
125
|
Abstract
Abstract
ASD research is at an important crossroads. The ASD diagnosis is important for assigning a child to early behavioral intervention and explaining a child’s condition. But ASD research has not provided a diagnosis-specific medical treatment, or a consistent early predictor, or a unified life course. If the ASD diagnosis also lacks biological and construct validity, a shift away from studying ASD-defined samples would be warranted. Consequently, this paper reviews recent findings for the neurobiological validity of ASD, the construct validity of ASD diagnostic criteria, and the construct validity of ASD spectrum features. The findings reviewed indicate that the ASD diagnosis lacks biological and construct validity. The paper concludes with proposals for research going forward.
Collapse
|
126
|
Rannals MD, Page SC, Campbell MN, Gallo RA, Mayfield B, Maher BJ. Neurodevelopmental models of transcription factor 4 deficiency converge on a common ion channel as a potential therapeutic target for Pitt Hopkins syndrome. Rare Dis 2016; 4:e1220468. [PMID: 28032012 PMCID: PMC5154382 DOI: 10.1080/21675511.2016.1220468] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 07/11/2016] [Accepted: 07/28/2016] [Indexed: 01/31/2023] Open
Abstract
The clinically pleiotropic gene, Transcription Factor 4 (TCF4), is a broadly expressed basic helix-loop-helix (bHLH) transcription factor linked to multiple neurodevelopmental disorders, including schizophrenia, 18q deletion syndrome, and Pitt Hopkins syndrome (PTHS). In vivo suppression of Tcf4 by shRNA or mutation by CRISPR/Cas9 in the developing rat prefrontal cortex resulted in attenuated action potential output. To explain this intrinsic excitability deficit, we demonstrated that haploinsufficiency of TCF4 lead to the ectopic expression of two ion channels, Scn10a and Kcnq1. These targets of TCF4 regulation were identified through molecular profiling experiments that used translating ribosome affinity purification to enrich mRNA from genetically manipulated neurons. Using a mouse model of PTHS (Tcf4+/tr), we observed a similar intrinsic excitability deficit, however the underlying mechanism appeared slightly different than our rat model - as Scn10a expression was similarly increased but Kcnq1 expression was decreased. Here, we show that the truncated TCF4 protein expressed in our PTHS mouse model binds to wild-type TCF4 protein, and we suggest the difference in Kcnq1 expression levels between these two rodent models appears to be explained by a dominant-negative function of the truncated TCF4 protein. Despite the differences in the underlying molecular mechanisms, we observed common underlying intrinsic excitability deficits that are consistent with ectopic expression of Scn10a. The converging molecular function of TCF4 across two independent rodent models indicates SCN10a is a potential therapeutic target for Pitt-Hopkins syndrome.
Collapse
Affiliation(s)
- Matthew D. Rannals
- Department of Neurobiology, School of
Medicine, University of Pittsburgh, Pittsburgh, PA,
USA
| | - Stephanie Cerceo Page
- Lieber Institute for Brain Development, Johns
Hopkins Medical Campus, Baltimore, MD, USA
| | - Morganne N. Campbell
- Lieber Institute for Brain Development, Johns
Hopkins Medical Campus, Baltimore, MD, USA
| | - Ryan A. Gallo
- Lieber Institute for Brain Development, Johns
Hopkins Medical Campus, Baltimore, MD, USA
| | - Brent Mayfield
- Lieber Institute for Brain Development, Johns
Hopkins Medical Campus, Baltimore, MD, USA
| | - Brady J. Maher
- Lieber Institute for Brain Development, Johns
Hopkins Medical Campus, Baltimore, MD, USA
- Department of Psychiatry and Behavioral
Sciences, Johns Hopkins School of Medicine, Baltimore, MD,
USA
- Department of Neuroscience, Johns Hopkins
School of Medicine, Baltimore, MD, USA
| |
Collapse
|
127
|
Fernandes D, Carvalho AL. Mechanisms of homeostatic plasticity in the excitatory synapse. J Neurochem 2016; 139:973-996. [PMID: 27241695 DOI: 10.1111/jnc.13687] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/25/2016] [Accepted: 05/27/2016] [Indexed: 11/30/2022]
Abstract
Brain development, sensory information processing, and learning and memory processes depend on Hebbian forms of synaptic plasticity, and on the remodeling and pruning of synaptic connections. Neurons in networks implicated in these processes carry out their functions while facing constant perturbation; homeostatic responses are therefore required to maintain neuronal activity within functional ranges for proper brain function. Here, we will review in vitro and in vivo studies demonstrating that several mechanisms underlie homeostatic plasticity of excitatory synapses, and identifying participant molecular players. Emerging evidence suggests a link between disrupted homeostatic synaptic plasticity and neuropsychiatric and neurologic disorders. Hebbian forms of synaptic plasticity, such as long-term potentiation (LTP), induce long-lasting changes in synaptic strength, which can be destabilizing and drive activity to saturation. Conversely, homeostatic plasticity operates to compensate for prolonged activity changes, stabilizing neuronal firing within a dynamic physiological range. We review mechanisms underlying homeostatic plasticity, and address how neurons integrate distinct forms of plasticity for proper brain function. This article is part of a mini review series: "Synaptic Function and Dysfunction in Brain Diseases".
Collapse
Affiliation(s)
- Dominique Fernandes
- CNC-Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,PDBEB-Doctoral Program in Experimental Biology and Biomedicine, Interdisciplinary Research Institute (III-UC), University of Coimbra, Coimbra, Portugal
| | - Ana Luísa Carvalho
- CNC-Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| |
Collapse
|
128
|
Pitt GS, Lee SY. Current view on regulation of voltage-gated sodium channels by calcium and auxiliary proteins. Protein Sci 2016; 25:1573-84. [PMID: 27262167 DOI: 10.1002/pro.2960] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 05/31/2016] [Indexed: 11/09/2022]
Abstract
In cardiac and skeletal myocytes, and in most neurons, the opening of voltage-gated Na(+) channels (NaV channels) triggers action potentials, a process that is regulated via the interactions of the channels' intercellular C-termini with auxiliary proteins and/or Ca(2+) . The molecular and structural details for how Ca(2+) and/or auxiliary proteins modulate NaV channel function, however, have eluded a concise mechanistic explanation and details have been shrouded for the last decade behind controversy about whether Ca(2+) acts directly upon the NaV channel or through interacting proteins, such as the Ca(2+) binding protein calmodulin (CaM). Here, we review recent advances in defining the structure of NaV intracellular C-termini and associated proteins such as CaM or fibroblast growth factor homologous factors (FHFs) to reveal new insights into how Ca(2+) affects NaV function, and how altered Ca(2+) -dependent or FHF-mediated regulation of NaV channels is perturbed in various disease states through mutations that disrupt CaM or FHF interaction.
Collapse
Affiliation(s)
- Geoffrey S Pitt
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY, 10065
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, 27710
| |
Collapse
|
129
|
Poo MM, Pignatelli M, Ryan TJ, Tonegawa S, Bonhoeffer T, Martin KC, Rudenko A, Tsai LH, Tsien RW, Fishell G, Mullins C, Gonçalves JT, Shtrahman M, Johnston ST, Gage FH, Dan Y, Long J, Buzsáki G, Stevens C. What is memory? The present state of the engram. BMC Biol 2016; 14:40. [PMID: 27197636 PMCID: PMC4874022 DOI: 10.1186/s12915-016-0261-6] [Citation(s) in RCA: 204] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The mechanism of memory remains one of the great unsolved problems of biology. Grappling with the question more than a hundred years ago, the German zoologist Richard Semon formulated the concept of the engram, lasting connections in the brain that result from simultaneous “excitations”, whose precise physical nature and consequences were out of reach of the biology of his day. Neuroscientists now have the knowledge and tools to tackle this question, however, and this Forum brings together leading contemporary views on the mechanisms of memory and what the engram means today.
Collapse
Affiliation(s)
- Mu-Ming Poo
- Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China.
| | - Michele Pignatelli
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Tomás J Ryan
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Susumu Tonegawa
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | - Kelsey C Martin
- Department of Biological Chemistry and Department of Psychiatry and Biobehavioral Studies, David Geffen School of Medicine, BSRB 390B, 615 Charles E. Young Dr. South, University of California, Los Angeles, CA, 90095, USA
| | - Andrii Rudenko
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Li-Huei Tsai
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Richard W Tsien
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - Gord Fishell
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - Caitlin Mullins
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - J Tiago Gonçalves
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Matthew Shtrahman
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Stephen T Johnston
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Fred H Gage
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Yang Dan
- HHMI, Department of Molecular and Cell Biology, University of California, Berkeley, USA
| | - John Long
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - György Buzsáki
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - Charles Stevens
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| |
Collapse
|
130
|
Excitation-Transcription Coupling in Parvalbumin-Positive Interneurons Employs a Novel CaM Kinase-Dependent Pathway Distinct from Excitatory Neurons. Neuron 2016; 90:292-307. [PMID: 27041500 DOI: 10.1016/j.neuron.2016.03.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 11/23/2015] [Accepted: 02/24/2016] [Indexed: 11/20/2022]
Abstract
Properly functional CNS circuits depend on inhibitory interneurons that in turn rely upon activity-dependent gene expression for morphological development, connectivity, and excitatory-inhibitory coordination. Despite its importance, excitation-transcription coupling in inhibitory interneurons is poorly understood. We report that PV+ interneurons employ a novel CaMK-dependent pathway to trigger CREB phosphorylation and gene expression. As in excitatory neurons, voltage-gated Ca(2+) influx through CaV1 channels triggers CaM nuclear translocation via local Ca(2+) signaling. However, PV+ interneurons are distinct in that nuclear signaling is mediated by γCaMKI, not γCaMKII. CREB phosphorylation also proceeds with slow, sigmoid kinetics, rate-limited by paucity of CaMKIV, protecting against saturation of phospho-CREB in the face of higher firing rates and bigger Ca(2+) transients. Our findings support the generality of CaM shuttling to drive nuclear CaMK activity, and they are relevant to disease pathophysiology, insofar as dysfunction of PV+ interneurons and molecules underpinning their excitation-transcription coupling both relate to neuropsychiatric disease.
Collapse
|